Screw Torque Calculator

Formula

The formula to calculate the screw torque is:

\[ T_s = K \cdot F \cdot d \cdot \left(1 - \frac{L}{100}\right) \]

Where:

\(T_s\) is the screw torque (lb-ft)
\(K\) is the material constant
\(d\) is the nominal bolt diameter (ft)
\(F\) is the axial bolt force (lbf)
\(L\) is the force lost due to lubrication (%)

What is Screw Torque?

The screw torque is the amount of torque required to tighten a screw or bolt. It is calculated based on the material constant, the diameter of the bolt, the axial bolt force, and the percentage of force lost due to lubrication.

Example Calculation 1

Let's assume the following values:

Material Constant (K) = 0.2
Bolt Diameter (d) = 0.25 ft
Axial Bolt Force (F) = 100 lbf
Force Lost Due to Lubrication (L) = 10%

Using the formula:

\[ T_s = 0.2 \cdot 100 \cdot 0.25 \cdot \left(1 - \frac{10}{100}\right) = 0.2 \cdot 100 \cdot 0.25 \cdot 0.9 = 4.5 \text{ lb-ft} \]

The Screw Torque is 4.5 lb-ft.

Example Calculation 2

Let's assume the following values:

Material Constant (K) = 0.15
Bolt Diameter (d) = 0.5 ft
Axial Bolt Force (F) = 150 lbf
Force Lost Due to Lubrication (L) = 5%

Using the formula:

\[ T_s = 0.15 \cdot 150 \cdot 0.5 \cdot \left(1 - \frac{5}{100}\right) = 0.15 \cdot 150 \cdot 0.5 \cdot 0.95 = 10.6875 \text{ lb-ft} \]

The Screw Torque is 10.6875 lb-ft.